Operation and Design of Single-Phase Grid-Connected Multi-Cascaded-Inverter Using LLC Converter Supplied by a Single Solar Photovoltaic [TMS320F28379D Implementation]

Operation and Design of Single-Phase Grid-Connected Multi-Cascaded-Inverter Using LLC Converter Supplied by a Single Solar Photovoltaic [TMS320F28379D Implementation]

• 1. Slide1 naschibo #power #electronics, #vienna, #austria, #energy Operation and Design of Single-Phase Grid- Connected Multi-Cascaded-Inverter Using LLC Converter Supplied by a Single Solar Photovoltaic [TMS320F28379D Implementation]
• 2. Slide13 The module-integrated inverter and micro-inverter, due to small size and low power rating of the converter, require voltage elevation for grid connection because of the low voltage rating of PV modules (generally around 30V). An advantage of using multilevel converters as PV inverters is related to the output waveforms high quality, reducing the grid connection filter needs, leading to a compact design for low power applications (usually domestic roof-top). This is why ac-module inverters are only found with an additional dc-dc stage, usually with a high frequency transformer to provide galvanic isolation and elevate voltage. Due to the low voltage operation, MOSFET devices are most commonly found in these topologies. Figure 1: INCEnergy – Single-Phase Grid-Connected Multi-Cascaded-Inverter
• 3. Slide18 LLC converter– Closed Loop The PWM signal generation is performed by C2000 Delfino MCUs F28379D LaunchPad Development Kit from Texas Instruments. The microcontroller is a fast instruction fixed-point microprosessor (200 MHz). Integrated on-chip peripherals such as serial port, timers, PWM module and peripheral interfaces units make the interfacing task much easier and with higher reliablity. Figure 2: C2000 Delfino MCUs F28379D LaunchPad Development Kit. Solar power converters benefits greatly of the good characteristics of WBG new devices and a large number of researchers present new developments both based on SiC and GaN devices and the comparison with their counterparts made of silicon is clearly favorable to the new devices [1], [2].
• 4. Slide19 For analog signal measurement, a 16-channel 10-bit A/D converter with programmable conversion time has been integrated on the CPU. This microcontroller is specially targeted towards industrial drives and servo motor control audiences. Apart from these applications, this part can be utilized to its fullest for solar inverters and converters, digital power, transportation and power line communications. The board shown in Figure 2 is used to develop, debug and execute application programs. Figure 3: Testing Workbench of Single-Phase Grid-Connected Multi-Cascaded-Inverter [Happly Lab, August 2018.]
• 5. Slide20 Figure 3: The PCB layout and circuit design of inverter by Eagle. LLC Analog Controller ICE2HS01G ICE2HS01G is Infineon’s 2nd generation half-bridge LLC controller designed especially for high efficiency half-bridge or full-bridge LLC resonant converter with synchronous rectification (SR) control for the secondary side. The maximum switching frequency is supported up to 1MHz. Apart from the patented SR driving techniques; this IC provides very flexible design and integrates full protection functions as well. It is adjustable for maximum/minimum switching frequency, soft-start time and frequency, dead time between primary switches, turn-on and turn-off delay for secondary SR MOSFETs. The integrated protections include input voltage brownout, primary three-levels over current, secondary over load protection and no-load regulation. It also includes a burst mode function which offers an operation with low quiescent current maintaining high efficiency at low output load while keeping output ripple voltage low.
• 6. Slide21 Figure 4: The input supply of LLC converter
• 7. Slide22 Figure 5: Control Layout
• 8. Slide23 Figure 6: PCB Layout of the whole system
• 9. Slide24 Furthermore, focus is put on the control of power electronic circuits, measuring and protection circuits, and the microcontroller. On the other hand, the auxiliary circuits are all designed and included, in order to make operational prototypes. The control system algorithm is performed using the MATLAB Simulink® model. The parameter values of the PID controllers of the system gains and the compensators are derived using this model. The AC voltage regulation is needed because of the non-linear loads. The entire control system is verified on a single-phase pulse-width- modulation (PWM) converter simulation with a simple DSP-based digital implementation of multi-cascade inverter. The controllers for stand-alone inverter are also tested under non-linear conditions (10 Ohm resistive load, 1mH inductive load and 75mF capacitive load). The PV system controllers consist of two stages, one is for the closed loop control Maximum Power Point Tracking (MPPT) of the DC-DC stage and the other for the closed loop control of the DC-AC stage. This project has presented the modeling of a stand-alone PV system using a special hybrid PWM method. The details of the modeling technique and circuitry simulations were described. The objective of this method is to fit the mathematical equations to the system and validate with circuitry simulation for the purpose of comparison. Analysis of the results shows that the model yields the similar performance as produced by the circuitry simulation. The TMS320F28379D and other ICs were used to maximize reliability, minimize complexity, minimize size (reduced PCB space) and minimize cost. A brief introduction on inverter that includes an overview of inverter power circuit topology, switching strategy and modulation technique has been presented. All the controllers have been designed by standard design techniques, and verified by simulation in MATLAB / SIMULINK.
• 10. Slide25 To verify the operations of grid-connected inverter, a simulation system based on a single-phase 2-level VSI is set up and the simulation is carried out in MATLAB/Simulink and PLECS environment. Moreover, LLC resonant half-bridge converter design example will be tested considering the parameters like total harmonic distortion and losses. The switching frequency will be altered from 1kHz to 20kHz to achieve best results. Finally, the sensitivity to ripple in voltage and current at the terminals of the PV module were considered. Acknowledgment The author of this paper would like to express their appreciation and sincere gratitude to Austrian Institute of Technology (A.I.T) for providing funding for this project. References [1] J. Rabkowski, D. Peftitsis and H. P. Nee, „Silicon Carbide Power Transistors: A New Era in Power Electronics Is Initiated,“ IEEE Industrial Electronics Magazine, vol.6, no.2, pp.17-26, June 2012. [2] R. Singh and M. Pecht, „Commercial impact of silicon carbide,“ IEEE Industrial Electronics Magazine, vol.2, no.3, pp.19-31, Sept. 2008
• 11. Slide16 http://www.incenerji.com https://www.researchgate.net/profile/Kayhan_Ince2 https://at.linkedin.com/in/kayhan-ince-09363018 THANK YOU FOR YOUR ATTENTION